Heart-shaped light bulb



FIG. 1 is a front elevational view of a heart-shaped light bulb showing my new design;

FIG. 2 is a right-hand elevation thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a left-hand side view thereof; and,

FIG. 6 is a rear view thereof. 

The ornamental design for a heart-shaped light bulb, as shown and described. 